1. Technical Field
The present disclosure generally relates to lens, and particularly relates to a liquid lens and a lens module including the liquid lens.
2. Discussion of Related Art
A zoom lens module typically includes at least one lens, an image sensor and an actuator, such as a step motor for driving the lenses to move relatively to the image sensor in order to obtain a desired focal length. However, the step motor is relative large in volume, thus a significant amount of space is needed for movement of the lenses, which makes it very difficult to reduce a volume of the lens module.
Optical systems employing liquid lenses are developed recently to meet a trend of miniaturization. As shown in FIG. 7, a typical liquid lens 400 includes an enclosure 410 which defines a receiving space (not labeled) and two types of liquids (an electrically conductive liquid 420 and an electrically insulative liquid 430) received in the receiving space. The two liquids are non-dissolved and non-wetable to each other. When applying a voltage to two electrodes (not shown) fixed on the enclosure 410, an electrowetting is produced, and a curvature of an interface 423 between the two liquid 420, 430 is varied because of the electrowetting, thus obtaining a desired focal length. However, after focusing, the voltage need be applied continuously to keep the curvature in place due to gravity influence of the electrically conductive liquid 420. Therefore, the optical system has a high power-consumption.
What is desired, therefore, is a liquid lens and a lens module having the same to overcome the above-described problems.